Well the wife and kids were gone this week so I did the t stat, greased the rear drive shaft u joints, fixed my AIR solenoid issue and decided to do the t case fluid as it was around the 80,000km mark. Now we have debated AT2 fluid for years on this and other forums. Never really came to any other consensus than: Use the approved AT2 fluid. It is inexpensive, when I changed it out maybe 5 to 6 years ago, 2 liters at the dealer cost me 16$ or so all in. This day and age a few companies have some dedicated t case fluid that meets the AT2 while others have ATF that meets AT2.
After much reading, I never really learned what AT2 actually was, why is it this secret? So I looked at the whole problem as objectively as I could. These systems came out years ago. GM had only a couple options for ATF. Dex 6 (approx. 5 cSt, low viscosity fluid) and the mineral based Dex 3 (approx. 7 cSt higher viscosity). Most everyone was using thicker fluid in the t cases so that left mineral based Dex 3, which apparently did not have the required or sufficient friction modifiers to work with the clutch pack. Who knows why this clutch pack is so special compared to the advanced systems in auto transmissions.. Anyways I began looking at two big names: Amsoil (who I think makes great products with absurd markup) and PetroCan (who are or at some point making various GM branded oils sold at the dealers in Canada). Both have a 7 cSt multi vehicle ATF that meets the AT2 requirement. Now before anyone jumps on me for the "meets" or "suitable for use" and not the licenced or approved caveats, I don't care. You have companies that clearly make licenced quality products but chose not to pay for the stamp. Anyway, PetroCan Duradrive and Amsoil multi vehicle ATF are the ones. Now what makes them special? Both start off with quality synthetic group 3/4 base stocks, which carry inherent viscosity/friction abilities (look at Amsoils HD SAE 30 diesel oil, which without viscosity improvers is able to meet SAE 10w cold flow). I have been using Amsoil LV multi ATF in the Trailblazer's transmission since 2014, 60,000km ago with not one issue but gasp, its not a licenced Dex 6 fluid!!!
So extrapolating from that I had 4 liters left over of my Co-op ATF SL. Its a 7 cSt multi vehicle formula. I had used this in my 2011 Ram 1500, 545RFE trans with great results. It is Canadian made by Co-op out here on the prairies. This company also makes licenced Dexos products so they can make good stuff. So this ATF is group 4 based and meets many of the same applications as the others. So whats the difference? Who really knows, it worked great in an ATF+4 application. I popped 2 liters in the t case, drove it around to get the fluid up to temp and circulated and then did some driving on the grid roads in auto 4wd. Much not to my surprise, the t case engaged as it should. No shuddering or clunking, just positive lockup. I did numerous launches to generate a difference in front/rear wheel spin and the t case did its job.
Now I will keep everyone posted long term. Someone had to be the guinea pig so if it crashes and burns, well, live by the sword.....
Oh and edit: Amsoil, last time I checked was about 15$ a quart before taxes in and around these parts. Duradrive was under 8$ a liter before taxes and the Co-op ATF was just a hair past 9$ a liter all in.
After much reading, I never really learned what AT2 actually was, why is it this secret? So I looked at the whole problem as objectively as I could. These systems came out years ago. GM had only a couple options for ATF. Dex 6 (approx. 5 cSt, low viscosity fluid) and the mineral based Dex 3 (approx. 7 cSt higher viscosity). Most everyone was using thicker fluid in the t cases so that left mineral based Dex 3, which apparently did not have the required or sufficient friction modifiers to work with the clutch pack. Who knows why this clutch pack is so special compared to the advanced systems in auto transmissions.. Anyways I began looking at two big names: Amsoil (who I think makes great products with absurd markup) and PetroCan (who are or at some point making various GM branded oils sold at the dealers in Canada). Both have a 7 cSt multi vehicle ATF that meets the AT2 requirement. Now before anyone jumps on me for the "meets" or "suitable for use" and not the licenced or approved caveats, I don't care. You have companies that clearly make licenced quality products but chose not to pay for the stamp. Anyway, PetroCan Duradrive and Amsoil multi vehicle ATF are the ones. Now what makes them special? Both start off with quality synthetic group 3/4 base stocks, which carry inherent viscosity/friction abilities (look at Amsoils HD SAE 30 diesel oil, which without viscosity improvers is able to meet SAE 10w cold flow). I have been using Amsoil LV multi ATF in the Trailblazer's transmission since 2014, 60,000km ago with not one issue but gasp, its not a licenced Dex 6 fluid!!!
So extrapolating from that I had 4 liters left over of my Co-op ATF SL. Its a 7 cSt multi vehicle formula. I had used this in my 2011 Ram 1500, 545RFE trans with great results. It is Canadian made by Co-op out here on the prairies. This company also makes licenced Dexos products so they can make good stuff. So this ATF is group 4 based and meets many of the same applications as the others. So whats the difference? Who really knows, it worked great in an ATF+4 application. I popped 2 liters in the t case, drove it around to get the fluid up to temp and circulated and then did some driving on the grid roads in auto 4wd. Much not to my surprise, the t case engaged as it should. No shuddering or clunking, just positive lockup. I did numerous launches to generate a difference in front/rear wheel spin and the t case did its job.
Now I will keep everyone posted long term. Someone had to be the guinea pig so if it crashes and burns, well, live by the sword.....
Oh and edit: Amsoil, last time I checked was about 15$ a quart before taxes in and around these parts. Duradrive was under 8$ a liter before taxes and the Co-op ATF was just a hair past 9$ a liter all in.
